JP3278245B2 - Plating equipment for plating materials with minute plating parts - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for plating a plated article having a minute plating portion.

[0002]

2. Description of the Related Art The "anode" of a plating apparatus includes a dissolved anode and an insoluble anode. The dissolving anode is for dissolving the metal in the plating solution,
Made of plated metal. The insoluble anode is made of platinum or the like so as not to be dissolved in the plating solution. In the case of the dissolving anode, sludge is generated on the surface of the dissolving anode, and there is a disadvantage that the plating solution is contaminated. Therefore, insoluble anodes are widely used at present.

[0003]

However, insoluble anodes are not without their drawbacks. That is, when the surface area of the insoluble anode is extremely large relative to the plating portion of the plating product, additives (such as a brightener) in the plating solution are decomposed on the surface of the insoluble anode. For example, when the plating area is extremely small with respect to the entire surface area of the plating object, such as in the case of bump plating on a wafer, the total area of the plating area is naturally extremely small with respect to the surface area of the insoluble anode. Therefore, in such a case, as described above, the additive in the plating solution is decomposed on the surface of the insoluble anode. This is due to an oxidation reaction at the anode portion, and the oxidation reaction decomposes additives required for plating deposition. As described above, since the additives in the plating solution are consumed by decomposition, conventionally, the additives must be frequently replenished during the plating operation.
It was very disadvantageous in terms of workability and cost.

The present invention has been made by paying attention to such a conventional technique, and provides a plating apparatus with less consumption of additives.

[0005]

According to the present invention, in order to achieve the above object, the present invention provides a plating apparatus for a plated product having a fine plating portion, wherein the surface area of the insoluble anode with respect to the total area of the fine plating portion is 0.5 to 0.5%. This is a range of 5 times.

[0006] Since the surface area of the insoluble anode is suppressed to 5 times or less in accordance with the total area of the microplated portions, the amount of the additive decomposed on the surface of the insoluble anode is small. In addition, since the surface area of the insoluble anode is at least 0.5 times (ie, 1/2) of the total area of the microplated portion, plating on the microplated portion can be performed without any trouble.

[0007] The plating method may be either an immersion type or a jet type. When applied to the jet type,
It is more preferable that the shape is such that the flow of the plating solution is not hindered and that a uniform current distribution is obtained for the minute plating portion.

[0008] In addition, Au, Ag, C
u, Sn, Pb, Sn / Pb, Ni, Pd, Pt, Rh
Any type of plating may be used.

Further, the additives whose decomposition is suppressed by the present invention include a brightener, a leveling agent, a surfactant and the like.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. 1 to 4 show a first embodiment of the present invention. This embodiment is a jet type plating apparatus for performing bump plating of a wafer 1. As shown in FIGS. 4 and 5, the wafer 1 has a silicon base 2 on which an aluminum vapor deposition layer 3 is formed, a barrier metal layer 4 is formed thereon, and a surface of about 100 μm diameter is further formed on the surface. The photoresist layer 5 is formed in a state where the minute plating portion P is left. A large number of plating portions P are formed on the plating surface 1a of the wafer 1, and bump plating 6 made of Cu is formed on the plating portions P. As described above, the plating portion P is very small, and the ratio of the total area S _{1 obtained} by totaling the areas of the plating portions P to the total surface area S ₂ of the plating surface 1 a is S ₁ : S ₂ = 1: It is 100.

Next, a plating apparatus for forming the bump plating 6 will be described with reference to FIGS. 7
Denotes a plating tank, which has a box shape as a whole, and an opening 7a is formed in an upper portion of the plating tank 7. An airbag 8 is provided around the opening 7a. The airbag 8 is in a contracted state when not in use. After the wafer 1 is placed on the opening 7 a, the air is inflated by pressure-feeding the air, and the inflated airbag 8 presses the peripheral edge of the wafer 1. be able to. The wafer 1 is placed with the plating surface 1a facing downward, and the plating surface 1a is connected to a cathode (cathode). Inside the plating tank 7, a rectifying plate 9 made of vinyl chloride (PVC) having a large number of holes 9 a formed therein for blowing a plating solution M of Cu toward the wafer 1 is provided. The insoluble anode 10 is provided on the current plate 9. The insoluble anode 10 has a wire shape wound in a mainspring (or mosquito coil) shape. The relationship between the total area S ₁ of the plating site P and the surface area S ₃ of the insoluble anode 10 is such that S ₁ : S ₃ = 1: 3. Then, a plating solution M is supplied from an injection pipe (not shown) formed at a lower portion of the plating tank 7, and the plating solution M is blown upward from a hole 9 a of the rectifying plate 9 via an insoluble anode 10, No. 1 plating surface 1a. The plating solution M having hit the plating surface 1a is collected at a lower portion of the plating tank 7, and is repeatedly jetted upward from a jet pipe (not shown). As described above, since the plating solution M continuously comes into contact with the plating surface 1a of the wafer 1, Cu ions in the plating solution M precipitate at the minute plating site P, and FIG.
The bump plating 6 as shown in FIG.

The plating solution M used in the plating tank 7
Has the following composition. Plating bath composition (copper sulfate plating solution) Metallic copper 28 g / l (preferably 25-35 g / l) sulfuric acid 200 g / l (180-250 g / l)
・ 70 mg / l of chlorine ion (preferably 50 to 90 mg / l) ・ 25 ml / l of organic brightener (preferably 20 to 30 ml / l) ・ Temperature 28 ° C.

In the composition of the plating solution M, the organic brightener is a component which is easily decomposed by contacting the insoluble anode 10, but in the plating apparatus of this embodiment, the amount decomposed during plating is very small. . Table 1 below shows a comparison between the decomposition and consumption of the organic brightener in this example and the decomposition and consumption of the organic brightener in a plating apparatus as a comparative example. Although not shown, the plating apparatus according to the comparative example has a rectifying plate itself made of platinum, and uses the rectifying plate itself as an insoluble anode. Therefore, the relationship between the total area S ₁ of the plating site P and the surface area S ₄ of the rectifying plate (insoluble anode) of the comparative example is S ₁ : S ₄ =
1: 200. Other structures are the same as in this embodiment.

[0014]

[Table 1]

As shown in Table 1, in the case of the example, decomposition and consumption of the organic brightener were smaller than in the comparative example. This is because the surface area S ₃ of the insoluble anode 10 of the embodiment is equal to the plating area P
Is suppressed to an area as small as about three times the total area S ₁ . On the other hand, in the case of the comparative example, since the surface area S ₄ of the insoluble anode (rectifying plate) is significantly larger than the total area S ₁ of the plating portion P, the amount of the organic brightener decomposed and consumed is large.

Further, the insoluble anode 10 of this embodiment
Has a wire shape wound in a spiral shape, and therefore does not hinder the flow of the plating solution M, and shows a uniform current distribution with respect to the plating surface 1 a of the wafer 1. Accordingly, the plating thickness of the bump plating 6 obtained in the example was substantially the same as that of the plating obtained in the comparative example, and the uniformity of the plating thickness was good. As described above, according to the plating solution of this embodiment, decomposition and consumption of the organic brightener can be reduced without lowering the original performance of the plating apparatus.

FIGS. 5 and 6 show an insoluble anode according to another embodiment of the present invention. The insoluble anode 12 may be a net-like insoluble anode 12 as shown in FIG. 5, or may be a zigzag insoluble anode 13 as shown in FIG. The point is that the surface area of the insoluble anodes 12 and 13 should be 0.5 to 5 times the total area of the plating site.

In each of the above embodiments, a jet type plating apparatus has been described. However, the present invention can be applied to an immersion type plating apparatus.

[0019]

According to the present invention, the plating apparatus for a plated product having a minute plating portion has the contents as described above, and the amount of decomposition and consumption of additives can be reduced. Therefore, the degree of replenishment of the additive during the plating operation is reduced, which is advantageous in terms of workability and cost. In addition, the amount of platinum and the like used for producing the insoluble anode can be reduced, and this is also advantageous in terms of cost.

[Brief description of the drawings]

FIG. 1 is a sectional view of a plating apparatus according to an embodiment of the present invention.

FIG. 2 is a perspective view showing an insoluble anode mounted on a current plate.

FIG. 3 is a perspective view showing a wafer.

FIG. 4 is an enlarged sectional view of a plating portion.

FIG. 5 is a perspective view showing an insoluble anode according to another embodiment.

FIG. 6 is a perspective view showing an insoluble anode according to another embodiment.

[Explanation of Signs] 1 Plating 10 Insoluble anode P Micro-plating area M Plating solution S ₁ Total area of micro-plating area S ₃ Surface area of insoluble anode

Claims (1)

(57) [Claims] 1. A plating apparatus for bringing a cathode-plated product having a minute plating portion and an insoluble anode into contact with a plating solution and depositing a metal in the plating solution on the minute plating portion of the plating product, The insoluble anode has a shape of a wire wound in a spiral shape, and has a surface area of the insoluble anode in the range of 0.5 to 5 times the total area of the microplated portion, the microplated portion being characterized in that: Plating equipment for plating.